Hydraulic pump or motor of the radial cylinder type



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4 HYDRAULIC PUMP OR MOTOR OF THE RADIAL CYLINDER TYPE Filed Oct. 8, 1943 3 Sheets-Sheet 1 Inventors wAiwwk (LAW: no pl 799mm Mama NA Wt $.Wdms

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A ltorney W. C. HOLDEN ET AL HYDRAULIC PUMP OR MOTOR OF THE RADIAL CYLINDER TYPE Filed 001?. 8, 1943 3 Sheets-Sheet 3 A tlorney Patented Aug. 19, 1947 HYDRAULIC PUMP on MOTOR or 'rnr:

RADIAL CYLINDER TYPE I Warwick Claude Holden Naylor, Monkseaton, Vickers-Armstrongs Limited, London, a company of Great Britain and Joshua Challiner England, assignors to England, I l

Application October 8, 1943, Serial No. 505,490 i In Great Britain June 25, 1942 Section 1, Public Law 690, August 8, 1946. Patent expires June 25, 1962 Claims. (Cl. 103-174) This invention relates to hydraulic pumps or motors of the kind having a number of spaced radially arranged cylinders each containing a piston in driving or driven connection with an eccentric carried by a driving or driven shaft.

The chief object of the present invention is to evolve an hydraulic pump or motor of simple and compact construction having a minimum number of moving parts and which will permit of extensive use of light alloys in its construction.

Such a construction of hydraulic pump or motor is particularly suitable for high speed operation for use on aircraft in connection with the usual hydraulic services and is suitable for use with extremely light anti-freezing oil-s or other fluids and under extreme temperature conditions.

An hydraulic pump or motor of the kind set forth and in accordance with the invention comprises a body containing or carrying a number of radially arranged cylinders and associated pistons, a valve chamber or end cover attached to one end of the body anda distance piece attached to the opposite end of the body or end cover, the body and distance piece containing bearings supporting a driving or driven shaft carrying an eccentric in driving or driven connection with the pistons, the valve chamber having fluid admission and exit ports and containing a self-sealing valve having an eccentric path of movement and actuated by an eccentric on the driving or driven shaft, the valve serving to control the flow of fluid through common fluid admission and exit ports leading to the cylinders.

I In order that the said invention may be clearly understood and readily carried into effect the same will now be more fully described with ref-- erence to the accompanying drawings, in which:

Figure l is a longitudinal vertical section on the line A--B in Figure 2 of an hydraulic pump or motor constructed in accordance with the present invention.

Figure 2 is a transverse fragmentary section the same on the line C-D in Figure 1.

Figure 3 is an end elevation illustrating the construction of the valve, the end cover of the body having been removed.

Figure 4 is a longitudinal vertical section illustrating a modified construction of hydraulic pump or motor.

Figure 5 is a fragmentary sectional view taken through the cylinders.

Figures 6 and '7 are fragmentary sectional views illustrating two alternative methods of coupling the pistons to the eccentric.

Referring in the first case to Figures 1-3 of the accompanying drawings, which illustrate hydraulic pump designed particularly foruse on aircraft in connection-with the usual hydraulic services, the pump comprises a body portion l to which are secured by means of studs 2 a series of sector shaped cylinder blocks 3, each bored radially to form a cylinder in which is slidably 'mounted a piston 4, each piston being bored transversely at its inner end to receive a transverse pin 5, the inner end of each piston being of part spherical shape as at 6 and being adapted to engage a part spherical seating 1 in a slipper 8, the slippers 8 being shaped on their inner surfaces to engage the exteriorsurface of a-ring 9 concentrically arranged about an eccentric l0 formed 'on the driving shaft ll. Needle bearings H are interposed between the eccentric and the inner surface of the ring 9 to permit of easy relative movement.

The pins 5 do not actually contact the slippers, the whole of the inward thrust to which the piston-s are subjected being transmitted to the slippers through the medium of the part spherical ends of the pistons and their co-operating part spherical seatings.

To restrain the pistons against undesired outward radial movement, two retaining rings l3 of angle section are provided which surround the pins 5, the latter being .cut away at their extremities, as shown in Figure 1, to substantially arcuate shape to permit of the retaining rings being of minimum diameter and thus incidentally reduce. the overall diameter of the pump.

The driving shaft ll is rotatably mounted within roller bearings l5 located within a distance piece I! having an attachment flange [8 for the attachment of the pump to an engine or other component with which it is to be associated, the driving shaft ll being formed with the usual splined extremity l9, the driving shaft H passing through a packing gland 20 inthe distance piece H. A further bearing I6 is provided for supporting the shaft at its opposite end.

Secured to the end of the driving shaft is an eccentrically operated valve 2| which may be of e the self sealing kind, the valve by virtue of its low surface speed being particularly suitable for use in high speed pumps or motors, the valve being of the sectional shape illustrated in Figure 1 and having inlet and discharge ports arranged as in Figure 3, the valve serving to control the flow of fluid to and from the cylinders by way of the common fluid supply and delivery passage 22, the valve operating between the pump body I and the valve chamber or end cover 23, the latter being formed with supply and delivery ports 24 and 25 for the entry and exit 01' the oil or other fluid. The said valve comprises two concentric parts 40 and 4| the outer of which, 4|, is freely journalled on the inner and is driven therefrom by means of a driving pin 42 mounted in the part 40 and adapted to engage between a pair of shoulders formed on the part 4|. inner part 40 is mounted in any suitable manner on an eccentric member 43 which is associated with the shaft, and by virtue of such eccentricity the whole valve i caused on rotation of the shaft II to move in an eccentric path over sealing faces 45 and 46 formed on the outer end of a cylinder block or barrel and on the inner surface of the end cover 23. The inner part 40 is formed with an operative face 49 of annular form opposed to the cylinder block which is adapted to control a ring of ports such as 50 forming the outer termini of the passages 22, which are arranged in the'sealing face 45 at a constant radius from the centre of the shaft while the outerpart 4| is also provided with an operative face adapted to slide over the inner face 46 of the end cover 23. A plurality of axially directed springs such as 52 are interposed between the two parts 40 and 4| in known manner to cause the operative faces 49 and 5| to bear against their respective sealing faces during those periods when the liquid pressurefalls below a predetermined value while a suitable sealing device is also provided between the periphery of the inner part 40 and the outer part 4| in order to prevent leakage of liquid between said parts. In the embodiment illustrated the sealing device comprises a ring 53 of flexible material which is of substantially U- shape in cross section and is disposed in a recess 54 formed between the parts 40 and 4|. Also located on the part 40 and adapted to cooperate with the ring 53 is a second ring 55 which may 'be formed of brass or other suitable material and provided with suitable conduits, channels or the like adapted to allow the pressure of liquid outside the valve to act on the ring 53 and cause the same to expand to effect a liquid seal between the two parts 40 and 4| The valve above described operates in such a manner that when liquid pressure is exerted from outside the valve it will act on the part 40 and force the operative face 49 of that part into contact with the sealing face 45. The pressure outside the valve also acts on the part 4| andforces the operative face 5| into contact with the sealing face 46 on the cover 23.

The modified form-of pump or motor illustrated by Figures 4 and 5 has'the main characteristics of the pump previously described, but in this case no big attempt has been made to maintain the overall diameter of the pump at a minimum.

In this arrangement the cylinders consist of simple borings in the body I, each cylinder being closed at its outer end by a screwed plug 26.

The supply of fluid to and from the cylinders i controlled by an eccentrically operated valve 2| as in the previously described construction, the fluid entering and leaving the pump or motor by way of ports 24 and 25. An additional fluid port 25a is provided leading to the fluid head tank to maintain a constant head of fluid to the p mp. 7

In this arrangement each piston is bifurcated as at 21 atits inner end and is fitted with a transversely arranged pin 28 on which is mounted a roller 29, the latter making'contact with a ring 4 9 concentrically arranged about the axis of the eccentric Hi, the ring 9 running on a series of needle bearings as in the construction hereinbefore described. If desired needle type bearings may be interposed between the rollers 29 and the pins 28.

In order to restrain movement of the pistons in an outward direction, two angle shaped floating retaining rings |3 are disposed around the pins 28 so that the pins engage their inner peripheral surfaces, the retaining rings also serving to prevent sliding movement of the pins 28 in an axial direction.

In the arrangement shown the pins 28 engage the floating rings direct but alternatively they may be fitted with rollers, which rollers engage the inner peripheries of the rings.

In the modified constructions illustrated by Figures 6 and 7 two alternative methods of coupling the pistons with the eccentric are shown. In the arrangement illustrated by Figure 6 the piston 4 is bifurcated as at 21 at its inner end and carries a roller 29 as in Figures 4 and 5, the roller engaging a ring 9 surrounding the eccentric l0, roller bearings 30 being interposed between the ring and eccentric.

A pin 28 is passed through the bifurcated parts 21, each pin being recessed as at 3| to receive the inner peripheral edges of the floating retaining rings l3, the bottom of each groove being shaped to conform with the peripheral curvature of its associated ring. The retaining rings are again of angle section but in this case their flanges are directed outwardly. The rings by virtue of their engagement in grooves in the pins and their surface contact with the side cheeks of'the bifurcated parts of the pistons prevent axial movement of the pins and any tendency for the pistons to turn about their own axes during. operation.

In the arrangement illustrated by Figure 7, the extremities of the pins 28 are actually cut away at 32 over approximately half their diameter, the parts of the pins not removed being shaped on their outer surfaces to conform to the inner peripheral shape of the rings, the latter being of rectangular shape in cross section. The rollers run in an annular peripheral groove 33 in the ring 9, needle type-bearings being interposed between the ring 9 and an inner race mounted on the eccentric. In this arrangement the interengagement of the rollers with the annular groove prevents not only axial turning movement of the pistons but also serves to locate the ring in an axial direction in spaced relationship with the adjacent parts of the eccentric and washer 34.

What we claim and desire to secure by Letters Patent of the United States is:

1. In a hydraulic pump or motor. a plurality of spaced radially arranged cylinders, a piston in each cylinder, a first eccentric, a rotatable shaft bearing the eccentric, the pistons being in operative connection with said first eccentric. a pump housing consisting of two end members and an intermediate member with the said rotatable shaft extending through one of said end members and the intermediate member and into said other end member, bearings for said shaft being arranged in said first end member and said first intermediate member, the said eccentric being carried by said shaft within said intermediate member,

' said cylinders being radially arranged in said intermediate member, a valve located within said second end member, a second eccentric on said shaft controlling said valve, and fluid ducts in said intermediate member controlled by said valve, said ducts communicating with said cylinders.

2. A hydraulic pump or motor as claimed in claim 1 wherein each piston is bifurcated at its inner end and is bored to receive a transversely arranged pin carrying a roller, the latter contacting an annular ring freely revolvably mounted about said first eccentric said first eccentric being mounted on the shaft within the intermediate member, said pins projecting at each end from the bifurcated parts and being engaged by two annular floating retaining rings, said rings surrounding the projecting ends of all of said pins and serving to maintain the rollers in contact with their associated ring, the projecting ends of said pins being notched or recessed on their outer surfaces to receive the inner edges of the surrounding annular retaining rings.

3. A hydraulic pump or motor as claimed in claim 1 wherein each piston is bifurcated at its inner end and is bored to receive a transversely arranged pin carrying a roller, each said roller contacting an annular ring freely revolvably mounted about said first eccentric said first eccentric being mounted on said shaft within said intermediate member, said pin projecting at each end from said bifurcated parts and being engaged by two annular floating retaining rings, said rings surrounding the projecting ends of all of said pins and serving to maintain the rollers in contact with their associated ring, the said transversely arranged pins being cut away at their extremities on their outer surfaces to receive said retaining rings, said annular rings with which the rollers contact being formed with a peripheral annular groove forming an annular guideway for the rollers.

4. An hydraulic pump or motor as claimed in claim 1 wherein each piston is formed with a semi-spherical inner end which is seated with-- in a semi-spherical seating in a slipper in contact with an annular ring freely revolvably mounted about said first eccentric, said first eccentric being mounted on the shaft within the intermediate member, each piston being bored to receive a transversely arranged pin, the extremities of said pins being cut away on their outer surfaces to engage annular floating retaining rings of angle section.

5. An hydraulic pump or motor as claimed in claim 1 wherein each piston is bifurcated and bored transversely at its inner end, a piston pin passing through said bore, a roller carried by said piston pin, an annular ring freely revolvably mounted about said first eccentric and being engaged by said rollers carried by said piston pins, each piston pin projecting at each end from the appropriate bifurcated part, two annular floating retaining rings contacting with and surrounding the projecting ends of all of said piston pins to maintain said rollers in contact with their associated ring.

WARWICK CLAUDE HOLDEN. JOSHUA CHALLINER NAYDOR.

REFERENCES CITED The following references are of record in the file of this patent:

, UNITED STATES PATENTS Number 

